This invention relates to apparatus for forming flaps on a carton after the carton has been packed, with the flaps correlated to the level of the top of the contents of the carton, and more particularly to such apparatus for scoring the walls of the carton at said level, slitting the corners of the carton down to said level, and trimming off the tops of the side walls of the carton.
The invention is especially concerned with apparatus for forming flaps on cartons packed with wrapped reams of paper (e.g., reams of 81/2 .times. 11 inches sheets of paper), although it is to be understood that apparatus made in accordance with the invention may be used for forming flaps on cartons packed with other commodities.
In general, reams of paper are presently packaged either in cartons which are pre-scored and pre-slit to have pre-formed top flaps or in cartons with separate lids. As to either of these systems, a relatively large number of different height cartons must be stocked. As to packaging reams in cartons with pre-formed top flaps, the height of the stack or stacks of reams in the carton may vary considerably, and this requires insertion of sheets of cardboard or corrugated board ("fillerboards") to fill whatever space there may be between the top of the reams and the folded-down flaps. This is wasteful of material (the fillerboards) and labor. As to use of separate lids, the lids may be pre-formed or folded in place on the cartons. In either case, material is wasted due to the necessary overlap of the sides of the lid and the carton, extensible strapping should be used, adding to the cost, and there are other disadvantages. Additional problems ensue from the present method of forming the sheets and stacking the sheets in reams (this method being referred to as "slitting and sheeting") due to this method resulting in entrapment of air between the sheets in the ream. This necessitates use of a carton of a height sufficient to accommodate the reams with the entrapped air. As the cartons lie in storage stacked one on top of another in a warehouse, the air eventually escapes, reducing the height of the reams in the cartons, thereby removing the support afforded the top of a carton by the reams, with resultant bulging and rupture of cartons.
The invention is in the same general class as U.S. Pat. No. 3,015,197, issued Jan. 2, 1962, which shows apparatus for slitting the corners of a carton down to the level of the top of its contents, and to fold the resultant flaps outwardly on fold lines at said level.